Posted by Mr. Obvious on 10/20/2011, 9:44 am, in reply to "Re: Question"

I believe- and correct me if I'm wrong here- that if you were to employ the use of non-rifled barrels, regardless of caliber or reasoning, that the firearm you're manufacturing/firing would be considered a Short-Barreled Shotgun if the barrel lengths are under 18 inches. As well, overall length of said firearm cannot be less than 26 inches.

I suppose if you really want to go that route, be sure to follow those guidelines- or ask ATF to be 100% certain, and then get it in writing.